Abstract: An embodiment of the invention relates to an optical device (10) comprising a coupler (20) having coupler inputs (I1, I2) and coupler outputs (O1-O4), and a connection network (30), wherein said connection network comprises connecting waveguides (41-44) which connect said coupler outputs with outputs of the connection network (O1?-O4?), and wherein at least one connecting waveguide of the connection network crosses at least one other connecting waveguide of the connection network. At least one connecting waveguide (42-44), which crosses other connecting waveguides less often than the connecting waveguide (41) with the maximum number of crossings with other connecting waveguides, is attenuated by an optical attenuation element (81-84, 91-94).